SiO_2气凝胶对罗丹明B的吸附动力学研究

Study on adsorption kinetics of silica aerogel for rhodamine B

研究SiO2气凝胶对罗丹明B的吸附动力学特征,考察溶液吸附剂用量、吸附时间、吸附温度及罗丹明B初始浓度对SiO2气凝胶吸附效果的影响。结果表明:吸附量随着气凝胶加入量的增大而减小,在吸附时间40min,吸附温度14℃,罗丹明B初始浓度为6mg/L时吸附效果较好。SiO2气凝胶对罗丹明B的吸附行为可用Langmuir和Frenundlich吸附等温式进行描述,相关性均较好,但更符合Frenundlich经验公式。采用一级动力学和二级动力学模型考察吸附过程,吸附过程符合二级动力学方程。

The adsorption property of silica aerogel for organic dye rhodamine B was discussed from the kinetic viewpoints.The adsorption of rhodamine B in water on Silica aerogel was investigated.The results showed that adsorption quantity was decreased with increase of the amount of aerogel.The adsorption effect was better when adsorption time40 min,adsorption temperature 14℃and the initial concentration of 6mg/L.The adsorption parameters of silica aerogel for Langmuir and Freundlich isotherm models were determined.Both isotherms were suited to analyzing the equilibrium data of adsorption.But the Freundlich model fitted better than the Langmuir model.The adsorption was tested with first-order kinetics model and the second-order kinetics model.Adsorption process conformed to the secondary dynamic equation.